"Tomorrow is the table read for our 100th episode!" showrunner Marlene King tweeted the day before Pretty Little Liars' table read. "I'm a bit too excited to sleep. But I guess I should try. Night all. I love you."

Who Killed Alison's Mom?

King's tweet is one of many spilling the beans on Pretty Little Liars' big 100. Cast and crew are excited about the super secret episode, and took to social media to express their joy. A few photos were posted from the April 28th read-around that leaked juicy secrets.

First of all, the episode, is written by King and is called Miss Me x 100.

Jenna Cavanaugh's name tag was at the at read-around, so most likely Toby's long lost step-sister will making an appearance.

Sydney Driscoll also had a name tag at the read around. Sydney will be played by Chloe Bridges who joins as the newest member of Rosewood High swim team. Check out Bridges' snap of PPL on her Instagram.

Also, Ezra got shot in the season 4 finale, but a snap of Ian Harding at the read-around signals he is likely going to be featured. Check hip grinning in matching hats on Lucy Hale's Instagram.

Post-production coordinator, Lauren Ann Steere, teased on her Twitter that Keegan Allen "couldn't make it today," when fans asked where he was (who plays Toby). So what does that mean for Toby? Steere continued that fans should expect "juicy stuff."

We know for sure that Caleb (Tyler Blackburn) is making his triumphant return to Rosewood after spin-off Ravenswood was cancelled. King confirmed in an earlier Enstars report that the 100th episode is the one in which Caleb makes his appearance.

King also hinted (in March) that some of the Ravenswood kids might show up too, "The [Ravenswood] kids are all fantastic and they have become good friends with Caleb, so it's certainly possible that they would come into his life when he returns to Rosewood.

 "I think there will definitely be a big reveal in the 100th episode -- it's going to be an emotionally epic episode," Marlene King previously told E! News.

Season 5 of Pretty Little Liars premieres on ABC Family on June 10 at 8 p.m.

Tags: pretty little liars Marlene King ABC Family television